SAUSAG 71 – 21 Aug 2014 Tech Tips Jerry Le Breton On behalf of the SAUSAG Committee

Did you know… ?  PERL regular expressions can be used by informats created with PROC FORMAT ? SAUSAG 71 – 21 Aug 2014 What’s a PERL regular expression? It’s a pattern matching (and substitution) “language”. Whole set of prx… functions available. This is validating the format of a time variable.

PERLy FORMATS SAUSAG 71 – 21 Aug 2014 Use the pattern to define an INFORMAT. The REGEXP option identifies the string as a regular expression. If matched, the time8. informat is used to return a SAS time value.

Curly PERLy FORMATS SAUSAG 71 – 21 Aug 2014 Pattern substitutions also possible

PERLy FORMATS  Why bother – can use PRX functions? Simpler programs Formats independent of programs - patterns can be changed without touching the programs that use the informats  See: Using the New Features in PROC FORMAT Rick Langston, SAS Institute Inc., Cary, NC Many other papers SAUSAG 71 – 21 Aug 2014

Metadata  “Data about data”  SAS Metadata Server underpinning SAS products since version 9  Metadata also buried in Base SAS data sets – for decades.  e.g. column labels, column formats, total observations, sorted status, …. SAUSAG 71 – 21 Aug 2014

Metadata – SAS Data Set SAUSAG 71 – 21 Aug 2014 Logical Components of a SAS Data Set SAS(R) 9.3 Language Reference: Concepts, Second Edition Metadata includes data set attributes, and column attributes e.g. column labels and formats

Data Set Descriptor Info SAUSAG 71 – 21 Aug 2014 Data Set label can be customised with useful stuff. Proc DATASETS controls most descriptor info.

Metadata – SAS Data Set SAUSAG 71 – 21 Aug 2014 Logical Components of a SAS Data Set SAS(R) 9.4 Language Reference: Concepts, Third Edition SAS 9.4 provides for any amount of custom metadata with Extended Attributes.

Data Set – Extended Attributes  Attributes for the data set e.g. the “as at” date of the data set  Attributes for the columns e.g. an explanation of a column’s derivation  Attributes are simply Name/Value pairs  You use Proc DATASETS to manage a data set’s extended attributes SAUSAG 71 – 21 Aug 2014

Data Set – Extended Attributes SAUSAG 71 – 21 Aug 2014 xattr statement for controlling extended attributes add a new attribute. ds indicates a data set extended attributes (rather than one for a variable) Name of extended attributes Value of extended attributes

Data Set – Extended Attributes SAUSAG 71 – 21 Aug 2014 New table in output of contents statement for data set extended attributes.

Variable – Extended Attributes SAUSAG 71 – 21 Aug 2014 Set the value of an extended attribute, ‘Privacy’, for the variable, Name.

Variable – Extended Attributes SAUSAG 71 – 21 Aug 2014 Multiple extended attributes can be set.

Variable – Extended Attributes SAUSAG 71 – 21 Aug 2014 Can store pre-calculated stats in extended attributes. Store anything in extended attributes – even the source program.

Accessing Extended Attributes SAUSAG 71 – 21 Aug 2014

Stored Extended Attributes SAUSAG 71 – 21 Aug 2014 Extended attributes in separate file: sas7bxat extension (indexes stored in files with sas7bndx extension)  Use SAS to copy/move the data set  Extended attributes propagate in simple processing  But check doco for anything more complicated.

Extended Attributions  Base SAS (R) 9.4 Procedures Guide, Third Edition Proc DATASETS  How to store data about your data in your data Chris Hemedinger, SAS Institute Inc  Developer Reveals: Extended Data Set Attributes Diane Olson, SAS Institute Inc., Cary NC SGF Paper SAUSAG 71 – 21 Aug 2014

Questions? SAUSAG 71 – 21 Aug 2014 I could use an extended attribute… Jerry Le Breton